The complete or partial detachment of ligaments, tendons and/or other soft tissues from their associated bones within the body are relatively commonplace injuries, particularly among athletes. Such injuries are generally the result of excessive stresses being placed on these tissues. By way of example, tissue detachment may occur as the result of an accident such as a fall, over-exertion during a work-related activity, during the course of an athletic event, or in any one of many other situations and/or activities.
In the case of a partial detachment, commonly referred to under the general term "sprain", the injury will frequently heal itself, if given sufficient time and if care is taken not to expose the injury to further undue stress. In the event that the soft tissue is completely detached from its associated bone or bones, however, surgery may be needed to re-attach the soft tissue to its associated bone or bones.
Numerous devices are currently available to re-attach soft tissue to bone. Examples of such currently-available devices include screws, staples, cement and sutures.
In certain situations, it is desirable to anchor one end of a length of conventional suture in bone so that the other end of the length of suture resides free outside the bone. The free end of the suture can then be used to re-attach soft tissue to the bone. Suture anchors for anchoring one end of a length of conventional suture in bone, and installation tools for deploying the same, are described and illustrated in U.S. Pat. Nos. 4,898,156; 4,899,743; and 4,968,315, which patents are hereby incorporated herein by reference.
Other known suture anchors are adapted to anchor an intermediate portion of a length of conventional suture in bone so that the two opposite ends of the length of suture reside free outside the bone. These two free ends of suture can then be used to re-attach soft tissue to the bone. Suture anchors of this latter type, and installation tools for deploying the same, are described and illustrated in U.S. Pat. Nos. 4,946,468 and 5,002,550 and in pending U.S. patent applications Ser. Nos. 07/902,513 and 07/837,061, which patents and patent applications are also hereby incorporated herein by reference.
Still other suture anchors and suture anchor installation tools are described and illustrated in U. S. Pat. Nos. 4,738,255 and 4,741,330. These latter patents are also hereby incorporated herein by reference.
In soft tissue re-attachment procedures utilizing suture anchors of the types described above, an anchor-receiving hole is generally first drilled in the bone at the desired point of tissue re-attachment. Then a suture anchor is deployed in the hole using an appropriate installation tool. This effectively locks the suture to the bone, with the free end(s) of the suture extending out of the bone. Next, the soft tissue is moved into position over the hole containing the deployed suture anchor. As this is done, the free end(s) of the suture is (are) simultaneously passed through or around the soft tissue, so that the free end(s) of the suture reside(s) on the far side of the soft tissue. Finally, the suture is used to tie the soft tissue securely to the bone.
Alternatively, in some soft tissue re-attachment procedures utilizing suture anchors of the types described above, the soft tissue may first be moved into position over the bone. Then, while the soft tissue lies in position against the bone, a single hole may be drilled through the soft tissue and into the bone. Next, a suture anchor is passed through the soft tissue and deployed in the bone using an appropriate installation tool. This results in the suture anchor being locked to the bone, with the free end(s) of the suture extending out of the bone and through the soft tissue. Finally, the suture is used to tie the soft tissue securely to the bone.
Unfortunately, in many situations it can be difficult for the surgeon to initially precisely identify the optimum point for tissue re-attachment. Frequently the surgeon must initially attach the soft tissue to the bone at his or her best approximation of the optimum re-attachment point. Thereafter, the patient's anatomy must be manipulated through a range of motions by the surgeon. This manipulation allows the surgeon to determine whether the tissue has been re-attached at the optimum location. If the tissue has not been re-attached at the proper location, the point of re-attachment must be relocated before moving forward with the remainder of the surgical procedure.
It will be understood, therefore, that regardless of which of the above-described anchoring procedures is used, the first re-attachment position may frequently have to be abandoned in favor of a more optimally located re-attachment position. This is generally not desirable, for a variety of reasons.
For one thing, it involves forming additional holes in the bone, and deploying additional suture anchors in those holes. At the same time, at least some of the original holes, containing generally irretrievable suture anchors, are ]left totally unused. Furthermore, if the new attachment point is located close to the original attachment point, as is frequently the case, the presence of holes in too close proximity to one another may weaken the integrity of the bone structure itself. This may in turn undermine the secure attachment of a suture anchor to the bone, or force the surgeon to chose a re-attachment point which is something less than optimal.